Glaciers How are Glaciers and Long Island related?
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Transcript of Glaciers How are Glaciers and Long Island related?
Glaciers
How are
Glaciers and Long Island
related?
Glaciers
Snowfall exceeds melting.
High altitudes and polar regions.
Gravity moves mass downhill.
Firn = very dense snow layer.
Continental Glaciers
Ice sheets that cover continents.
Kilometers thick.
Only 2 exist:
- Greenland and Antarctica
Valley Glaciers
Begins in a cirque = bowl-shaped basin at mountaintop.
Crevasses = cracks in the glacier.
Erosion
U-shaped Valleys
Cirques, Aretes and Horns.
Hanging Valleys - from tributary
Erosion
Striations = parallel scratches on bedrock... from rocks on bottom of glacier
Polish = fine material rubs rock smooth.
Striations
Polish
DepositionMoraines - Unsorted pile of debris = till
Erratics = large isolated boulders.
Drumlins = long, low mounds of till with teardrop shape.
Outwash Plain (sorted) = sediments that are “washed out” in front of glacier.
Erratic
Central Park, NYC
Drumlin
Lakes
Kettle Formation:
Kettle Lakes
Glacial LakeForms when ice dams a stream.
Ice Age Glacier Limit